49 lines
1.4 KiB
Python
Executable file
49 lines
1.4 KiB
Python
Executable file
#!/usr/bin/env python
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import itertools
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import sys
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from copy import deepcopy
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from typing import Iterator, List, Tuple
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Grid = List[List[str]]
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def update(grid: Grid) -> Grid:
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def neightbours(x: int, y: int) -> Iterator[Tuple[int, int]]:
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for dx, dy in itertools.product(range(-1, 2), range(-1, 2)):
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if dx == 0 and dy == 0:
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continue
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new_x, new_y = x + dx, y + dy
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while 0 <= new_x < len(grid) and 0 <= new_y < len(grid[0]):
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if grid[new_x][new_y] in "L#":
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yield new_x, new_y
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break
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new_x, new_y = new_x + dx, new_y + dy
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new_grid = deepcopy(grid)
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for x, y in itertools.product(range(len(grid)), range(len(grid[0]))):
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num_alive = sum(grid[nx][ny] == "#" for nx, ny in neightbours(x, y))
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if num_alive == 0 and grid[x][y] == "L":
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new_grid[x][y] = "#"
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elif num_alive >= 5 and grid[x][y] == "#":
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new_grid[x][y] = "L"
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return new_grid
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def solve(grid: Grid) -> int:
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while (new_grid := update(grid)) != grid:
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grid = new_grid
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return sum(sum(pos == "#" for pos in line) for line in grid)
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def main() -> None:
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input = [line.strip() for line in sys.stdin.readlines()]
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print(solve([[line[i] for i in range(len(line))] for line in input]))
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if __name__ == "__main__":
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main()
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